1. Field of the Invention
The present invention relates to a wireless communication system. More particularly, the present invention relates to a resource allocation method and an apparatus for the wireless communication system using subframe generated by dividing frequency-time resource in time domain.
2. Description of the Related Art
Generally, mobile communication systems provide subscribers with voice communication services on the move. With rapid technological advancements, the mobile communication systems can now also support high speed data communication services. However, there is a need for more sophisticated mobile communication systems to mitigate resource shortage and meet the high-speed service requirements of the subscribers.
Long Term Evolution (LTE) is a next generation broadband communication technology developed by the 3rd Generation Partnership Project (3GPP) in order to meet such requirement. The LTE system is a technology for realizing high-speed packet-based downlink communication at up to 100 Mbps. In order to fulfill the requirements for the LTE system, discussions are being held on various aspects: one scheme for reducing the number of nodes located in a communication path by simplifying a configuration of the network, and another scheme for maximally approximating wireless protocols to wireless channels.
In the aforementioned wireless communication system, resource allocation is performed in unit of a subframe. A sub-frame includes a plurality of sub-carriers/Resource Elements (REs) across a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols, wherein the sub-carriers can be contiguous or non-contiguous in the frequency domain, and the OFDM symbols can also be contiguous or non-contiguous in the time domain. In order to maintain generality, the following description is made under the assumption that a sub-frame consists of a plurality of contiguous sub-carriers across a plurality of contiguous OFDM symbols. The resources in a sub-frame can be further partitioned into Resource Blocks (RBs), and an RB can be assigned to one or more connected User Equipments (UEs) in a multi-user Multiple Input Multiple Output (MIMO) transmission mode.
A control channel is designed to carry the control signaling including Downlink Control Information (DCI) format for downlink resource allocation purpose. The design of control channel may vary from system to system. In 3GPP LTE Release 8, Physical Downlink Control Channel (PDCCH) consists of the first few OFDM symbols of each sub-frame. A UE looks for its DCI format in PDCCH region and, if found, reads the information therein for the present transmitted sub-frame. A DCI format for downlink communication includes information on RB resource allocation, Modulation and Coding Scheme (MCS), Hybrid Adaptive Repeat Request (HARQ) parameters, and the like.
A subframe can be categorized into one of a normal subframe and an Almost-Blank Sub-Frame (ABSF) subframe. In the legacy system, ABSF is designed to carry no scheduling or data to avoid interference in a situation where at least two networks are deployed in the same location or with overlapped coverage.
However, the mal-configured ABSF is likely to degrade resource utilization efficiency in the resource wireless communication system.
Therefore, a need exists for a method and an apparatus for scheduling data transmission in ABSF that is capable of reducing scheduling overhead.